1. Field of the Invention
The present invention relates to a one-way clutch of roller type used as a part such as a torque transmitting element or a back stopper in a driving apparatus of a motor vehicle, an industrial machine and the like, for example. More particularly, the present invention relates to a one-way clutch of roller type suitable to be used as a starter of a motor bike.
2. Related Background Art
In general, a one-way clutch of roller type is comprised of an outer race having at least one pocket provided at its inner periphery with a cam surface, an inner race disposed in concentric with the outer race and having an outer peripheral track surface, a roller disposed within the pocket and adapted to transmit torque between the outer peripheral track surface of the inner race and the inner peripheral cam surface of the outer race, and a spring contacted with an idle rotation side of the roller.
With this arrangement, in the one-way clutch, the inner race is designed so as to be rotated only in one direction with respect to the outer race by means of a cam mechanism constituted by the roller and the cam surface. That is to say, the inner race is designed so that it is idly rotated relative to the outer race in one direction, and on the other hand, it applies rotational torque to the outer race via the cam mechanism only in an opposite direction.
In some one-way clutches of roller type used as the starter of the motor bike, as disclosed in Japanese Patent Application Laid-open No. 5-044615 (1993), a side plate provided at its inner diameter portion with spline grooves with which a member such as a crankshaft of an engine is engaged is bolted to an outer race of the one-way clutch.
On the other hand, in order to enhance the performance of the one-way clutch, it has been proposed to lubricate the members. For example, the above-mentioned Japanese Patent Application Laid-open No. 5-044615 (1993) discloses an arrangement in which a one-way clutch is lubricated by oil. Further, some one-way clutches have been used under a dry condition without oil lubrication.
In the conventional one-way clutch of roller type used as the starter of the motor bike as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 5-044615 (1993), it is feared that abrupt and excessive torque generated by the “kick-back” during the starting of the motor bike and/or erroneous engagement of the one-way clutch is applied to the one-way clutch through a crankshaft. Thus, it is necessary to strongly couple the side plate and the outer race by means of bolts or screws having reliable strength.
Accordingly, under a severe service condition that the motor bike is subjected to vibration, it is feared that the screw(S) is/are loosened, which will result in reduction in reliability of the one-way clutch.
Further, in order to prevent the screw from being loosened, it is necessary to fabricate means for preventing the screw from being loosened or to provide locking means such as lock-tight, which obstructs reduction in cost.
Further, since it is necessary to provide threaded holes in the outer race and the side plate and since the number of manufacturing steps is increased, there by increasing the cost.
Therefore, in the one-way clutch of roller type used as the starter of the motor bike having the side plate, it is desired to provide a one-way clutch of roller type in which reliability can be enhanced in comparison with conventional clutches and the cost can be reduced by decreasing the number of manufacturing steps.